The present invention relates to endotracheal tubes for mechanically ventilating patients, and also to an intubation system including such tubes.
In the medical treatment of patients requiring breathing assistance, it is frequently necessary to insert an endotracheal tube into the trachea of the patient, by way of the mouth or nose and to connect the tube to a ventilator which periodically forces air into the lungs through the tube. The inner or distal end of the tube is typically provided with an inflatable cuff which is inflated into contact with the interior wall of the trachea.
In using such endotracheal tubes, however, problems arise with respect to bodily secretions which pass progressively between the inner surface of the trachea and the outer surface of the cuff. The evacuation of secretions accumulated in the subglottal region above the cuff is required to prevent a ventilator-associated lung infection, commonly called VAP or Ventilator Associated Pneumonia. Attempts have been made in the past to overcome these problems by regulating cuff pressure and/or by suctioning secretions from between the trachea's wall and the endotracheal tube. The removal of such secretions by suction generally requires the insertion into the subglottal region of an external lumen having a suction inlet port located above the sealing cuff. Another alternative is to use a suction lumen integrally formed in the wall of the endotracheal tube. In either case, the suction lumen is connected to a negative pressure source, thus drawing out secretions within the subglottal region.
However, there is a tendency for the suction lumen to become blocked, particularly during long-term intubation. Attempts have made to prevent or reduce such suction lumen blockage by irrigating the suction channel between successive suctions. Such attempts, however, have frequently been unsuccessful, thereby subjecting the patient to an increase in the risk of lung infection.